Adhesion between Nuclear Particles

Electrons (very small sub-atomic particles) are therefore the fundamental cause of molecular attractions. These were the first elementary particles to be 

The simplest way to view the three forces of nature is in terms of density. Newton s weak gravitational force dominates our Solar System where the average density is around 10 kgm . On Earth, where the density is about 1000 kg m , electromagnetic forces are dominant and these are the main topic of this book. However, in the densest stellar objects, neutron stars, the strong force is dominant because the density is that of nuclear particles, around 10 kg The adhesion between such particles must be inunense. 

External crust sotid mass of nuclei in sea of electrons 

Neutron fluid regioti where nuclei are dissolved 

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Better candidates for the study of acoustic emission are composite materials. The extremely brittle polyvinyltoluene sample which showed easily detectable acousic emission (6) was indeed to some extent such a composite material since it was a sample used for scintillation counting of nuclear radiation. The crystalline particles of the inorganic scintillator embedded in the rather rigid polymer matrix differ enough in elastic properties from those of the matrix that a substantial stress enhancement occurs on the interface between the two components. One has about twice the bulk stress on the poles and one third on the equator of a perfectly rigid spherical particle. Such a stress increase in the poles leads rather early to adhesion failure of the particle-matrix boundary and to microcrack formation. This finally makes the sample fail at small strain-to-fracture, cb = 0.5%. The microcracks act as nuclei for crazing. The opening of a fissure between the particle and the matrix is sufficiently... 

The adhesive forces may also vary with the roughness of the particle. Thus, the adhesive force between the particles of coke shape [152] possessing microscopic surface roughness and a plane surface is smaller than that of smooth spherical particles of the same material. This is because contact between the coke-shaped particles and the plane is effected at individual points, which reduces the contact area and hence the adhesive force. Coke-shaped powders include coal and silica gel particles [153] as well as particles of dust and ashes formed in nuclear explosions in carbonate soils (coral reefs), when the soil particles are decarburized and acquire a flocculent shape [157] similar to that of coke. In general, powders of coke shape may be obtained by combustion of the volatile components from the particle surface. 

Yan et al. [52] explored the use of IPN techniques to produce a composite vinyl-acrylic latex. The first-formed polymer was produced using VAc and divinyl benzene (DVB), while the second formed polymer constituted a BA/DVB copolymer. In both cases the DVB was added at 0.4 wt%. They compared this product with another product, a bidirectional interpenetrating netwodc (BIPN) in which VAc was again polymerized over the first IPN. They noted that the compatibility between the phases was more pronounced in the BIPN than in the IPN as determined using dynamic mechanical measurements and C nuclear magnetic resonance spectroscopy. The concept of polymer miscibility has also been used to produce composite latex particles and thus modify the pafamance properties of VAc latexes. Bott et al. [53] describe a process whereby they bloid VAc/ethylene (VAc/E) copolymers with copolymers of acrylic acid or maleic anhydride and determine windows of miscibility. Apparently an ethyl acrylate or BA copolymer with 10-25 wt% AA is compatible with a VAc/E copolymer of 5-30 wt% ethylene. The information obtained from this woik was then used to form blends of latex polymers by polymerizing suitable mixtures of monomers into preformed VAc/E copolymers. The products are said to be useful for coating adhesives and caulks. 

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